Quick Start

Prerequisites

Before you start following this guide, make sure you have completed these three prerequisites.

Install and run Mistral

Go through the installation manual: Mistral Installation Guide

Install Mistral client

To install mistralclient, please refer to Mistral Client / CLI Guide

Export Keystone credentials

To use the OpenStack command line tools you should specify environment variables with the configuration details for your OpenStack installation. The following example assumes that the Identity service is at 127.0.0.1:5000, with a user admin in the admin tenant whose password is password:

$ export OS_AUTH_URL=http://127.0.0.1:5000/v2.0/
$ export OS_TENANT_NAME=admin
$ export OS_USERNAME=admin
$ export OS_PASSWORD=password

Write a workflow

For example, we have the following workflow.

---
version: "2.0"

my_workflow:
  type: direct

  input:
    - names

  tasks:
    task1:
      with-items: name in <% $.names %>
      action: std.echo output=<% $.name %>
      on-success: task2

    task2:
      action: std.echo output="Done"

This simple workflow iterates through a list of names in task1 (using with-items), stores them as a task result (using the std.echo action) and then stores the word “Done” as a result of the second task (task2).

To learn more about the Mistral Workflows and what you can do, read the Mistral DSL specification

Upload the workflow

Use the Mistral CLI to create the workflow:

$ mistral workflow-create <workflow.yaml>

The output should look similar to this:

+------------------------------------+-------------+--------+---------+---------------------+------------+
|ID                                  | Name        | Tags   | Input   | Created at          | Updated at |
+------------------------------------+-------------+--------+---------+---------------------+------------+
|9b719d62-2ced-47d3-b500-73261bb0b2ad| my_workflow | <none> | names   | 2015-08-13 08:44:49 | None       |
+------------------------------------+-------------+--------+---------+---------------------+------------+

Run the workflow and check the result

Use the Mistral CLI to start the new workflow, passing in a list of names as JSON:

$ mistral execution-create my_workflow '{"names": ["John", "Mistral", "Ivan", "Crystal"]}'

Make sure the output is like the following:

+-------------------+--------------------------------------+
| Field             | Value                                |
+-------------------+--------------------------------------+
| ID                | 49213eb5-196c-421f-b436-775849b55040 |
| Workflow ID       | 9b719d62-2ced-47d3-b500-73261bb0b2ad |
| Workflow name     | my_workflow                          |
| Description       |                                      |
| Task Execution ID | <none>                               |
| State             | RUNNING                              |
| State info        | None                                 |
| Created at        | 2017-03-06 11:24:10                  |
| Updated at        | 2017-03-06 11:24:10                  |
+-------------------+--------------------------------------+

After a moment, check the status of the workflow execution (replace the example execution id with the ID output above):

$ mistral execution-get 49213eb5-196c-421f-b436-775849b55040

+-------------------+--------------------------------------+
| Field             | Value                                |
+-------------------+--------------------------------------+
| ID                | 49213eb5-196c-421f-b436-775849b55040 |
| Workflow ID       | 9b719d62-2ced-47d3-b500-73261bb0b2ad |
| Workflow name     | my_workflow                          |
| Description       |                                      |
| Task Execution ID | <none>                               |
| State             | SUCCESS                              |
| State info        | None                                 |
| Created at        | 2017-03-06 11:24:10                  |
| Updated at        | 2017-03-06 11:24:20                  |
+-------------------+--------------------------------------+

The status of each task also can be checked:

$ mistral task-list 49213eb5-196c-421f-b436-775849b55040

+--------------------------------------+-------+---------------+--------------------------------------+---------+------------+---------------------+---------------------+
| ID                                   | Name  | Workflow name | Execution ID                         | State   | State info | Created at          | Updated at          |
+--------------------------------------+-------+---------------+--------------------------------------+---------+------------+---------------------+---------------------+
| f639e7a9-9609-468e-aa08-7650e1472efe | task1 | my_workflow   | 49213eb5-196c-421f-b436-775849b55040 | SUCCESS | None       | 2017-03-06 11:24:11 | 2017-03-06 11:24:17 |
| d565c5a0-f46f-4ebe-8655-9eb6796307a3 | task2 | my_workflow   | 49213eb5-196c-421f-b436-775849b55040 | SUCCESS | None       | 2017-03-06 11:24:17 | 2017-03-06 11:24:18 |
+--------------------------------------+-------+---------------+--------------------------------------+---------+------------+---------------------+---------------------+

Check the result of task ‘task1’:

$ mistral task-get-result f639e7a9-9609-468e-aa08-7650e1472efe

[
    "John",
    "Mistral",
    "Ivan",
    "Crystal"
]

If needed, we can go deeper and look at a list of the results of the action_executions of a single task:

$ mistral action-execution-list f639e7a9-9609-468e-aa08-7650e1472efe

+--------------------------------------+----------+---------------+-----------+--------------------------------------+---------+----------+---------------------+---------------------+
| ID                                   | Name     | Workflow name | Task name | Task ID                              | State   | Accepted | Created at          | Updated at          |
+--------------------------------------+----------+---------------+-----------+--------------------------------------+---------+----------+---------------------+---------------------+
| 4e0a60be-04df-42d7-aa59-5107e599d079 | std.echo | my_workflow   | task1     | f639e7a9-9609-468e-aa08-7650e1472efe | SUCCESS | True     | 2017-03-06 11:24:12 | 2017-03-06 11:24:16 |
| 5bd95da4-9b29-4a79-bcb1-298abd659bd6 | std.echo | my_workflow   | task1     | f639e7a9-9609-468e-aa08-7650e1472efe | SUCCESS | True     | 2017-03-06 11:24:12 | 2017-03-06 11:24:16 |
| 6ae6c19e-b51b-4910-9e0e-96c788093715 | std.echo | my_workflow   | task1     | f639e7a9-9609-468e-aa08-7650e1472efe | SUCCESS | True     | 2017-03-06 11:24:12 | 2017-03-06 11:24:16 |
| bed5a6a2-c1d8-460f-a2a5-b36f72f85e19 | std.echo | my_workflow   | task1     | f639e7a9-9609-468e-aa08-7650e1472efe | SUCCESS | True     | 2017-03-06 11:24:12 | 2017-03-06 11:24:17 |
+--------------------------------------+----------+---------------+-----------+--------------------------------------+---------+----------+---------------------+---------------------+

Check the result of the first action_execution:

$ mistral action-execution-get-output 4e0a60be-04df-42d7-aa59-5107e599d079

{
    "result": "John"
}

Congratulations! Now you are ready to use OpenStack Workflow Service!